Fixes regression bug in serializer.
Fixes regression bug in serializer.

baalexander/node-xmlrpc,AfterShip/node-xmlrpc,xmlrpc-js/xmlrpc-marshalling,hobbyquaker/homematic-xmlrpc,Growmies/node-xmlrpc,patricklodder/node-xmlrpc,MiniGod/node-gbxremote,bolster/node-xmlrpc